Edwin becker



Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE EDWIN BECKER, orBERLIN-,I-IERMSDORF, GERMANY PROCESS OF MANUFACTURING GRINDING ANDPOLISHING DISKS No Drawing. Application filed April 6, 1927, Serial No.181,598, and in Germany March 16, 1926.

It is known to give to grinding and polishing disks to be produced inpressing-moulds a dense structure preferably towards the centre bygiving to the disk a first shape in which the dimensions of the disk aregreater towards the middle'than they are intended to be in the finalshape. This was effected in such a manner that the preliminary shape wasproduced in one mould and the final shape in a second mould.

This manufacturing method presents the inconvenience that the mould hasto be changed, and it presents the danger that during the changing ofthe mould the kneadability decreases so that the preliminarily mouldeddisk easily crumbles to pieces in the second mould.

To obviate these inconveniences the material is pressed, according tothe invention, in one and the same pressing mould first to the coarsepreliminary shape by corresponding gradual accumulation of the materialat those points on which the greater density has to be obtained,whereupon with the aid of press ing rams shaped in accordance with thefinal shape this final shape is given to the material.

According to the improved method the mass filled into the pressing mouldis not distributed uniformly but in an inclined plane rising from theedges to the centre and compressed accordingly, so that the preliminaryshape is given to the material. In the samepressing mould the finalshape is given to the material by pressure. after the upper pressing ramhas been inserted into the mould. For equalizing the densities, the

pressing mould with the material is then turned upside down and a secondcompressing is carried out.

- I claim A process of pressing grinding and polishing disks byirregular "density by heaping the material on the point of the intendedcompression, consisting in distributing the material in the. mould fromthe edge towards .the center in an ascending plane, in submit-

